University of Oulu

Rissanen J, Helanterä H and Freitak D (2022) Pathogen Prevalence Modulates Medication Behavior in Ant Formica fusca. Front. Insect Sci. 2:870971. doi: 10.3389/finsc.2022.870971

Pathogen prevalence modulates medication behavior in ant Formica fusca

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Author: Rissanen, Jason1,2; Helanterä, Heikki2,3; Freitak, Dalial1,2
Organizations: 1Institute of Biology, University of Graz, Graz, Austria
2Tvärminne Zoological Station, University of Helsinki, Hanko, Finland
3Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.4 MB)
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Language: English
Published: Frontiers Media, 2022
Publish Date: 2023-01-09


Ants face unique challenges regarding pathogens, as the sociality which has allowed them to form large and complex colonies also raises the potential for transmission of disease within them. To cope with the threat of pathogens, ants have developed a variety of behavioral and physiological strategies. One of these strategies is self-medication, in which animals use biologically active compounds to combat pathogens in a way which would be harmful in the absence of infection. Formica fusca are the only ants that have previously been shown to successfully self-medicate against an active infection caused by a fungal pathogen by supplementing their diet with food containing hydrogen peroxide. Here, we build on that research by investigating how the prevalence of disease in colonies of F. fusca affects the strength of the self-medication response. We exposed either half of the workers of each colony or all of them to a fungal pathogen and offered them different combinations of diets. We see that workers of F. fusca engage in self-medication behavior even if exposed to a low lethal dose of a pathogen, and that the strength of that response is affected by the prevalence of the disease in the colonies. We also saw that the infection status of the individual foragers did not significantly affect their decision to forage on either control food or medicinal food as uninfected workers were also foraging on hydrogen peroxide food, which opens up the possibility of kin medication in partially infected colonies. Our results further affirm the ability of ants to self-medicate against fungal pathogens, shed new light on plasticity of self-medication and raise new questions to be investigated on the role self-medication has in social immunity.

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Series: Frontiers in insect science
ISSN: 2673-8600
ISSN-E: 2673-8600
ISSN-L: 2673-8600
Volume: 2
Article number: 870971
DOI: 10.3389/finsc.2022.870971
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
1184 Genetics, developmental biology, physiology
Copyright information: © 2022 Rissanen, Helanterä and Freitak. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.